1. Field of the Invention
The present invention relates to a lens barrel, and more particularly to a lens barrel which includes a barrier cylinder protecting a lens.
2 . Description of the Related Art
Previously, a lens barrel that extends from an image pickup apparatus body at the time of capturing an image and that retracts inside the body at the time of storage has been proposed. Such a lens barrel includes a retraction mechanism that is configured by a combination of a plurality of straight moving cylinders and rotational cylinders to extend and retract lens units in an optical axis direction. Furthermore, a lens barrier mechanism (barrier cylinder) that covers a front of a lens at a retracted position and that evacuates from the front of the lens when use, in conjunction with the retraction mechanism, has been proposed.
When for example a plurality of barrier blades are configured to overlap with each other in order to reduce the size of the lens barrel, it is necessary to have a certain space in the optical axis direction. In addition, when the length of a cam cylinder or a straight moving cylinder that moves in conjunction with the cam cylinder is increased in order to shorten the length of retraction, the cam cylinder and the straight moving cylinder are intruded into a space of a first cylinder that constitutes the barrier mechanism, and thus a space of parts that constitute the barrier mechanism is limited. Therefore, in order to reduce the size of the barrier mechanism and a barrel apparatus, it is required to efficiently dispose component parts of the barrier mechanism.
Japanese Patent Laid-open No. 2012-150173 discloses a barrel in which a plurality of barrier blades overlapping with each other are moved in conjunction with a bent portion from the barrier blade toward an imaging plane side and a locking portion using a thickness of the blade to achieve a thinned configuration.
In order to shorten the length of retraction of the lens barrel by reducing the size of the barrier mechanism, and particularly by thinning the size in the optical axis direction, the relation of the barrier blade and a spring that biases the barrier blade is important. It is because reducing (thinning) the size in the optical axis direction is inhibited if the barrier blade and the spring are disposed to be laminated along the optical axis direction.